1. Field of the Invention
The present invention relates to a vibration-damping support device for use in an automotive cab mount, a body mount, a sub-frame mount or the like, for example.
2. Description of the Related Art
Conventionally, there is known a vibration-damping support device interposed between connection targets that make up a vibration transmission system and providing vibration damping linkage therebetween, which is employed as a cab mount or the like, as disclosed in Japanese Unexamined Patent Publication No. JP-A-2004-291795. The vibration-damping support device includes an inner shaft member attached to a first connection target such as a cabin, an upper plate projecting peripherally outward from a first end of the inner shaft member, and an upper mount rubber disposed between opposed faces of a second connection target such as a vehicle frame and the upper plate. Moreover, with the vibration-damping support device, the inner shaft member is inserted into a mounting hole of the second connection target, and a lower plate projecting peripherally outward is provided to a second end of the inner shaft member on the opposite side from the first connection target, while a lower mount rubber is disposed between opposed faces of the second connection target and the lower plate. With the vibration-damping support device mounted to a vehicle, compression spring of the upper mount rubber and the lower mount rubber will support a load in the axial direction in a vibration damping manner.
Meanwhile, as disclosed in JP-A-2004-291795, in general, a rigid upper restraining member is bonded to the portion of the upper mount rubber to be superposed against the second connection target. The upper mount rubber is restrained by the upper restraining member on the side of superposition against the second connection target, thereby adjusting spring of the upper mount rubber or the like so as to realize desired supporting ability.
However, by superposing the upper restraining member and the second connection target, which are both rigid, with no bonding, a large input in the vertical direction sometimes causes relative displacement of the upper restraining member and the second connection target, generating noise due to rubbing. In particular, the inventor conducted researches and tests or the like, and found that the displacement of the upper restraining member relative to the second connection target is also caused by the lower mount rubber being subjected to a large compressive deformation in the axial direction and swelling so as to be inserted into the mounting hole of the second connection target, thereby pushing the upper restraining member and the upper mount rubber upward.